African tropical wave 99L has potential to develop

By: Dr. Jeff Masters , 3:10 PM GMT on July 30, 2012

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The first African tropical wave of 2012 with a potential to develop is Invest 99L, located in the Eastern Atlantic near 9°N 36°W, midway between the Lesser Antilles Islands and the coast of Africa. Visible satellite loops show a large area of the surrounding atmosphere has a pronounced counter-clockwise spin, though there is no surface circulation. The disturbance's heavy thunderstorm activity is pretty sparse, but appears to be slowly increasing. Water vapor satellite loops show that 99L has a reasonably moist environment, and the latest Saharan air layer analysis shows that the dry air from the Sahara lies well to the north of 99L. WInd shear over the disturbance is a light 5 - 10 knots, and ocean temperatures are 28°C, (82°F) which is well above the 26.5°C (80°F) threshold typically needed to allow formation of a tropical depression.


Figure 1. Morning satellite image of Invest 99L.

Forecast for 99L
Wind shear is expected to remain light for the next five days, and ocean temperatures will remain near 28°C, according to the 8 am EDT run of the SHIPS model. The disturbance is at 9°N, which is close enough to the Equator that the storm will have some difficultly getting spinning. Most of the models are showing some slow development of 99L, with the storm reaching the Lesser Antilles Islands on Saturday, August 3. NHC gave 99L a 20% chance of developing into a tropical depression by Wednesday morning. I expect the storm will have trouble with dry air at times this week as it crosses the Atlantic, but I give 99L a 50% chance of eventually developing into Tropical Storm Ernesto sometime in the next ten days. Residents and visitors to the Lesser Antilles Islands should anticipate heavy rains and strong winds from 99L beginning to affect the islands as early as Friday night. The long-range fate of 99L is uncertain, but a trough of low pressure is expected to be present over the Eastern U.S. early next week, which would be capable of turning 99L more to the northwest.

Hot in the Central U.S.
The heat in America's heartland continued on Sunday, with Wichita, KS hitting 111°F, just 3° short of their all-time hottest temperature of 114° set on 8/12/1936. Other notable highs on Sunday:

111° Coffeyville, KS
111° Winfield, KS
110° Chanute, KS
110° Parsons, KS
109° Joplin, MO (all-time record is 115° on July 14, 1954)

The low temperature in Tulsa, Oklahoma this Monday morning dropped to only 88°F. This is the all-time warmest low temperature in the city since record keeping began in 1905. The previous record warmest minimum temperature was 87°F set on August 2, 2011 and July 16, 1980. The high in Tulsa Monday - Wednesday is expected to reach 110° - 111°, close to the city's all-time hottest temperature of 115° set on August 10, 1936.

Jeff Masters

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Thanks Dr. Masters and good morning everyone.
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Thanks Dr. Masters.
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Those are some incredible temperatures, and there's not much relief expected for the next two weeks at least.

hot

In fact, the 8-14 day temperature outlook for most of the nation looks downright toasty:

hot
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As I said yesterday..thats either one huge tropical wave or the HPC is covering where it may track at.

Member Since: August 19, 2006 Posts: 13 Comments: 13451
The long-range fate of 99L is uncertain, but a trough of low pressure is expected to be present over the Eastern U.S. next week, which would be capable of turning 99L more to the northwest.
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Quoting stormchaser19:
we don't need talk more about the 99l ,Dr. Jeff Masters said everything we needs to know
Their are bloggers on here that live on the various land masses that could be affected no?.
Member Since: August 14, 2010 Posts: 10 Comments: 15707
Thx Dr Masters.
I wouldnt quite say 50%, but it is up there maybe 40%
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we don't need talk more about the 99l ,Dr. Jeff Masters said everything we needs to know
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Repost from last blog:

144 hrs. makes it into the Caribbean this one needs to be watch not just for impacts that it could have to the US in the long range, but for impacts it will most likely have on the Leeward/Windward Islands in the short range.

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Looks like we will see Atlantic action now ... seems to brewing all the way back to Africa with a parade coming

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Doc thank you for the update, seems we all should keep following the movement of 99L. Thank you for providing this service.
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Thanks Dr. Masters!

I expect the storm will have trouble with dry air at times this week as it crosses the Atlantic, but I give 99L a 50% chance of eventually developing into Tropical Storm Ernesto sometime in the next ten days.
Member Since: August 19, 2006 Posts: 13 Comments: 13451
Yo!! Taz, Ya here mate????

I should of listened to you from the start. But my kind self thought I should give him a chance. In the end, you were right.

I Apologise how I reacted to you last night.
Friends again Mate!!


_________________________________________________ _____________________________________________

Just released...
Severe Weather Bulletin Number ELEVEN
Tropical Cyclone Warning: Typhoon "GENER" (SAOLA)
Issued at 11:00 p.m., Monday, 30 July 2012
Typhoon "GENER" has maintained its strength and is now heading towards Eastern Taiwan.

Location of Center:
(as of 10:00 p.m.)
240 km East Northeast of Basco, Batanes

Strength: Maximum sustained winds of 120 kph near the center
and gustiness of up to 150 kph

Movement: North Northwest at 7 kph

Forecast Positions/Outlook: Tuesday evening
245 km Northeast of Basco, Batanes
Wednesday evening
420 km North of Basco, Batanes
Thursday evening
640 km North Northwest of Basco Batanes
outside the Philippine Area of Responsibility (PAR)

Areas Having Public Storm Warning Signal
Signal No.3
(100-185 kph winds) Batanes Group of Islands
Signal No. 2
(61-100 kph winds) Cagayan
Calayan Group of Islands
Babuyan Group of Islands
Signal No. 1
(45-60 kph winds) Isabela
Kalinga
Apayao

Typhoon "GENER" is expected to enhance the Southwest Monsoon that will bring rains and moderate to strong winds over Luzon and Visayas especially the western section.

Residents living in low lying and mountainous areas are alerted against possible flashfloods and landslides. Likewise, those living in coastal areas under Public Storm Warning Signal #3 and #2 are alerted against big waves or storm surges generated by this tropical cyclone.

Estimated rainfall amount is from 10 - 20 mm per hour (heavy - intense) within the 700 km diameter of the Typhoon.

Fishing boats and other small seacrafts are advised not to venture out into the Seaboard of Luzon and Visayas due to the combined effect of Typhoon "Gener" and the Southwest Monsoon.

The public and the disaster coordinating councils concerned are advised to take appropriate actions and watch for the next bulletin to be issued at 5 AM tomorrow.
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Thank you Dr. It looks like the islands will get some rain.
Member Since: March 28, 2008 Posts: 0 Comments: 1532
Quoting washingtonian115:
Thanks Doc.Topic of the day..Tropics!
instead of....topics! LOL
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Member Since: August 6, 2011 Posts: 4 Comments: 33346
Quoting washingtonian115:
Thanks Doc.Topic of the day..Tropics!

Haha its about time :p
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Quoting washingtonian115:
Thanks Doc.Topic of the day..Tropics!
LOL.
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Thanks Doc.Topic of the day..Tropics!
Member Since: August 14, 2010 Posts: 10 Comments: 15707

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.